The invention concerns a rear view mirror arrangement, especially an outside mirror for commercial vehicles.
Outside mirrors of this kind and of variously different construction, are already known in the present state of the technology. A mirror pane is adjustably affixed by a pivoting mechanism to a housing part, which is appropriately connected to the body of the vehicle, allowing the mirror to swing in reference to the housing part. The housing part is, as a rule, a solid plastic part, produced by injection molding. It is generally of a basin-like construction in which further mirror components or corresponding connection points for additions are installed. In particular, for large truck and bus mirrors, the carrying structure for outside mirrors is based on tubing or plates, which are affixed directly to the mirror holder which projects toward the vehicle body. This construction is disclosed by EP-A-0 590 510. The housing part serves then as a covering of the back side of the mirror plate and supports the pivoting mechanism. The housing also provides a streamlined sheathing of the outside mirror. Such construction is extremely expensive and heavy.
A problem with this tube and plate construction is found in that relatively strong vibrations occur in the rearview mirror assembly during the operation of the vehicle. In order to reduce these vibrations, EP 0 865 967 A2 proposes a carrying tube structure, encased in a foamed molded part. Again, the disadvantage of this is that the entire carrying structure is very heavy.
A very light design, which is adaptable to smaller mirrors, is taught by DE 44 29 604 A1. In this case, the tube construction is fully dispensed with and the foam element itself remains as the carrying structure. For this purpose, a gradiated foam is employed as a one-piece element or the carrier comprises several shells.
The objective of the present invention is to make available a sufficiently stable rearview mirror, which, in any case, exhibits the least possible tendency to vibrate. This purpose is accomplished by the features of the invention.
Because at least one hollow space in the carrier is filled with a filling material (also called fill material hereafter), which is composed of material other than that of the carrier, or which material possesses a density other than that of the carrier, it is possible to specifically target the vibratory tendencies of the carrier by the appropriate choice of filling material. Additionally the filling material can also lead to an improved stability of the carrier, insofar as the filling material binds itself to the inner wall of the carrier or the interior surface of the hollow space.
A plurality of hollow spaces within the carrier can purposely be provided at specific locations. The choice of the locations is done empirically, wherein the effort is made to bring about the greatest possible damping of the vibration.
The carriers with hollow spaces can be made by injection molding, foam processing such as a thermoplastic, integral foam, or blow molding, including extrusion blow molding. In these methods, for the applicable shape of the hollow spaces, negative shapes are inserted, which are patterned after the desired form.
In accord with an advantageous embodiment of the invention, for additional stabilization, stiffening structures are installed in at least one hollow space. This, in a first instance, can be brought about by inserting a separate component into a hollow space, or, in a second instance, in that the wall structure of the hollow space is provided with reinforcing ribs.
In accord with another advantageous embodiment of the invention, the filling material in the hollow spaces consists of plastic foam, such as polyurethane foam, gradient foam, multi-component hard foam and the like, which binds itself firmly with the interior walls of the hollow spaces, thus increasing the stability of the carrier. Moreover, by means of an appropriate choice of foam density, or by the resilience thereof, the vibratory behavior of the carrier can be so positively affected that during commercial travel, the inevitable vibrations are strongly damped and, as a result, the abrasion therefrom is reduced.
Additionally, or alternatively, it is possible to fill in the hollow space or spaces, or a part thereof, with a viscous material, in particular a gel or a gelatin-like material. In this way, likewise, the vibrations and the damping are specifically influenced.
In accord with a further advantageous embodiment of the invention, a granulate and/or sand may be additionally or alternatively placed in the hollow spaces or in a part thereof. In this way, the fill material can be comprised exclusively of sand or granulate, or a mixture thereof, or yet of a mixture with the above described gel, gelatin or foam. Once again, the stability is favored in a positive way and again the specific vibratory and damping characteristics can be advantageously controlled with attention to specifics.